基于微观视角的农村居民点发展评价与布局优化——以陕西省重点示范镇沙河子镇为例

将生态位态势理论应用于农村居民点布局研究,从发展水平和发展潜力两方面选取指标分别作为发展"态"和发展"势"的评价因素,构建农村居民点发展评价模型,对居民点的发展实力划分等级。然后结合加权Voronoi图,明确各发展等级居民点的搬迁去向,从而实现全镇整治分区规划。沙河子镇农村居民点的发展实力可划分为高、中、低和不适宜发展4个等级;农村居民点整体发展较好,高、中发展实力级的居民点用地面积为304.07hm2,占全区的84.23%;具有明显的地形分异特征,其发展等级呈现由中部向南北两侧递减的趋势;全镇以农村居民点城镇化为整理重点,划分为城镇化区、优先发展区、改造发展区和控制发展区4种整治分区。结合生态位态势理论和加权Voronoi图的农村居民点合理布局研究具有较强的现实指导意义。     

Land use changes and sea level rise may induce a “coastal squeeze” on the coasts of Veracruz,Mexico

“Coastal squeeze” refers to the process in which coastal ecosystems are threatened by the combination of sea level rise (SLR) and the presence of a physical barrier, such as human infrastructure. This situation prevents the landward migration of ecosystems and species, as the coastline moves inland, and they are thus exposed to local extinction. Our objective was to explore coastal squeeze in the state of Veracruz, Mexico, through the study of urban expansion on the coast, an analysis of coastline geodynamics, and a projection of the potential effect of SLR on the distribution of two focal plant species which are endemic to the coastal dunes of Mexico. Urbanization of the coast, parallel to the shoreline, has been taking place increasingly rapidly, displacing ecosystems, both natural (mangroves, beaches and coastal dunes) and transformed (cultivated fields and pastures). Taking into consideration the geodynamic trends of the coastline and an analysis of its historical evolution, it can be seen that the coastal strip is eroding at rates that vary from slow to very rapid. Finally, the results of ecological niche modeling indicate that, under scenarios of SLR, the potential distribution of the two focal species would diminish: Chamaecrista chamaecristoides by 6–28%, and Palafoxia lindenii by 2–15%. These results indicate that “coastal squeeze” is likely in the study area, and that measures to limit or mitigate this process are required. Such measures could include urbanization programs which limit development to appropriate zones, the restoration and rehabilitation of deteriorated ecosystems and the conservation of those ecosystems which are still healthy.     

Analysis of coprolites from the extinct mountain goat Myotragus balearicus

Humans colonized the Balearic Islands 5–4 ka ago. They arrived in a uniquely adapted ecosystem with the Balearic mountain goat Myotragus balearicus (Bovidae, Antilopinae, Caprini) as the only large mammal. This mammal went extinct rapidly after human arrival. Several hypotheses have been proposed to explain the extinction of M. balearicus. For the present study ancient DNA analysis (Sanger sequencing, Roche-454, Ion Torrent), and pollen and macrofossil analyses were performed on preserved coprolites from M. balearicus, providing information on its diet and paleo-environment. The information retrieved shows that M. balearicus was heavily dependent on the Balearic box species Buxus balearica during at least part of the year, and that it was most probably a browser. Hindcast ecological niche modelling of B. balearica shows that local distribution of this plant species was affected by climate changes. This suggests that the extinction of M. balearicus can be related to the decline and regional extinction of a plant species that formed a major component of its diet. The vegetation change is thought to be caused by increased aridity occurring throughout the Mediterranean. Previous hypotheses relating the extinction of M. balearicus directly to the arrival of humans on the islands must therefore be adjusted.     

如何把握《普通地质学》教学中的广度与深度

《普通地质学》作为地球科学类学生本科教育入门的专业启蒙和引导课程,不仅担负着专业知识体系引导而且还要培养学生正确的人生观和价值观的重任。因此,广度和深度就成为《普通地质学》课程教学改革的两个重要方面,课前准备需要把握知识点的广度,课堂教学需要把握知识点的深度,而广度与深度的相互交融是引导学生兴趣的关键,进而依托“趣味—科学—普适—经典”的教学方式,承担起大类人才培养模式下的素质教育职责。课程的改革任重道远,需要从多方面的努力和思考,方可达到预期的课程目标。     

地理要素的分布式空间近似查询处理方法

针对传统空间查询无法满足地理数据交互式可视化对处理时间要求的问题,以窗口查询为例,提出了一种空间近似查询处理方法。该方法包括预处理和查询两步:在预处理阶段,利用分布化的线简化算法对空间对象进行顾及误差的预处理采样,将采样过程及误差值用树型结构保存;在查询阶段,以豪斯多夫距离定义数据可视化的误差,进行误差可知的顶点即时采样与截取,从而实现针对可视化应用的高效的空间近似查询处理。在Hadoop集群上利用77GB的OpenStreetMap数据集进行了实验,证实了本方法的效力与效率。     

湖北省长湖浮游植物优势种生态位分析

于2012年4月至2013年1月对长湖浮游植物群落结构特征进行调查分析,使用Levins生态位宽度公式和Levins重叠公式测定长湖浮游植物优势种的生态位指数,分析浮游植物站点分布和环境因子的变化与生态位间的关系.结果显示:整个区域以蓝藻门和绿藻门的种类为主,优势种种类和密度随季节变化,表现出1~2个种类成为主要优势种,在丰度、优势度和生态位宽度上远大于其他优势种的特征.依据优势度指数和生态位宽度将优势种分为3类;小球藻(Chlorella vulgaris)和扭曲小环藻(Cyclotella comta)作为4个季节优势种,占据更多的资源位点,有更大的生态位宽度,在竞争中处于优势.蓝藻门的两栖颤藻(Oscillatoria amphibia)在夏季成为主要优势种,其丰度远大于其他种类,但受到种间竞争及高等水生植物的抑制,没有在竞争中取得绝对优势.其他种在不同季节此消彼长,但仅在若干季节成为优势种.海子湖区周围的进出水口及马洪台区、圆心湖区的围网养殖会直接影响水体中总氮、总磷浓度,进而改变浮游植物优势种在各区域的分布,使用t检验证实了这种差异.环境因子与优势种的相关性分析显示,水温、N/P比是影响浮游植物优势种分布的重要因素.     

Considering river structure and stability in the light of evolution: feedbacks between riparian vegetation and hydrogeomorphology

River ecological functioning can be conceptualized according to a four‐dimensional framework, based on the responses of aquatic and riparian communities to hydrogeomorphic constraints along the longitudinal, transverse, vertical and temporal dimensions of rivers. Contemporary riparian vegetation responds to river dynamics at ecological timescales, but riparian vegetation, in one form or another, has existed on Earth since at least the Middle Ordovician (c. 450 Ma) and has been a significant controlling factor on river geomorphology since the Late Silurian (c. 420 Ma). On such evolutionary timescales, plant adaptations to the fluvial environment and the subsequent effects of these adaptations on fluvial sediment and landform dynamics resulted in the emergence, from the Silurian to the Carboniferous, of a variety of contrasted fluvial biogeomorphic types where water flow, morphodynamics and vegetation interacted to different degrees. Here we identify several of these types and describe the consequences for biogeomorphic structure and stability (i.e. resistance and resilience), along the four river dimensions, of feedbacks between riparian plants and hydrogeomorphic processes on contrasting ecological and evolutionary timescales. Copyright © 2014 John Wiley & Sons, Ltd.     

A niche model to predict Microcystis bloom decline in Chaohu Lake, China

Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation (R=0.998, P<0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms.     

民间信仰地域分异的微观分析——泉州三个村庄神祇生态位宽度测量和比较

民间信仰区域分异,前人的研究多数定位于有方言差异的大尺度区域。但无方言差异的小尺度区域内,人们对神祇的信仰和供奉也存在一定的差异。本文利用生态位理论及生态位宽度测度模型对泉州市东海镇三个不同村落(蟳埔、宝山和法石)的民间神祇信仰情况进行微观分析。结果显示,在无方言差异的小尺度区域内,影响神祇在区域内生态位宽度的最主要因素是神祇功能与这个区域产业类型的相关程度。神祇的功能与区域内产业类型的相关程度是影响民间信仰神祇区域分异的重要因素。区域间产业类型的分异受自然地理条件的影响。因此,特定功能神祇的区域分异与自然地理环境有密切关系。由生态位宽度测度模型计算出的民间信仰神祇生态位数据与神祇在三个村落的分布及影响的实际情况比较契合,生态位理论应用于民间信仰神祇的区域研究是可行的。     

基于生态位理论的深莞惠旅游一体化策略研究

运用生态位理论对推进深莞惠三市旅游一体化进行分析,发现三地存在旅游资源生态位同质化和旅游产业发展生态位同向化的问题,因此要求三地厘清生态位,错位发展,开发特色旅游产品和旅游商品;扩充生态位,挖掘潜力,提供旅游发展的持续动力;分离生态位,在政府协调基础上进行旅游地分工;集中优势,共同打造跨区域特色旅游线路;建立深莞惠无障碍旅游区,巩固区域内旅游市场。